1. Technical Field
The present invention relates to a vehicle occupant protection apparatus including an inflatable vehicle occupant protection device, such as an air bag. In particular, the present invention relates to an air bag module in which inflation fluid is selectively vented from the module in order to control the speed and force of deployment of the air bag.
2. Description of the Prior Art
It is known to inflate an air bag to help protect a vehicle occupant in the event of sudden deceleration such as occurs in a vehicle collision. The air bag is stored in a deflated condition, together with an inflator, in a housing adjacent to the vehicle seat in which the occupant sits. The inflator, when actuated, provides a large volume of inflation fluid to inflate the air bag into a position to help protect the vehicle occupant.
Under normal circumstances, substantially all of the inflation fluid from the inflator is directed into the air bag to inflate the air bag. In some circumstances, however, it may be desirable to control or limit the amount of inflation fluid directed into the air bag. For example, if the vehicle occupant is smaller than a predetermined size or is closer to the vehicle instrument panel than a predetermined distance, then it may be desirable to reduce the speed and force with which the air bag inflates. It is known to vent inflation fluid from the housing of an air bag module in such circumstances, so that less inflation fluid is directed into the air bag.
The present invention is a vehicle occupant protection apparatus comprising an inflatable vehicle occupant protection device having a deflated condition and an inflated condition for helping to protect a vehicle occupant. An inflator is actuatable to provide inflation fluid to inflate the inflatable device. A retainer is connected with the protection device. One of the inflator and the retainer is movable between a first condition blocking venting of inflation fluid from the apparatus and a second condition venting inflation fluid from the apparatus. The apparatus includes an electrically energizable mechanism to release the one of the inflator and the retainer for movement from the first condition to the second condition to vent inflation fluid from the apparatus. The apparatus also includes vehicle electric circuitry including a sensor for sensing at least one occupant condition or vehicle condition and a controller responsive to the sensor for controlling the electrically energizable mechanism.